Conventional solid-state, high-power amplifiers (HPAs) used for wideband applications may have an octave or greater bandwidth. For these HPAs, the second harmonic (and possibly higher order harmonics) generated while operating at lower frequencies will fall within the amplifier's upper frequency band. Thus, the lower-band harmonics will not be filtered out by the amplifier matching networks, resulting in the HPA outputting large undesired signals at harmonic frequencies.
One typical solution to this problem is to implement a dual narrow band HPA with low harmonic output. However, conventional dual narrow band HPAs include switches or diplexers at the input and output of the HPA, which increase the size of the chip and result in loss. Also, adding either switches or diplexers at the output of the HPA will degrade the output power and efficiency of the HPA.